Molecular basis of the behavior of hepatitis a virus exposed to high hydrostatic pressure

Porcine parvovirus VP1/VP2 on a time series epitope mapping: exploring the effects of high hydrostatic pressure on the immune recognition of antigens

Porcine parvovirus (PPV) is a DNA virus that causes reproductive failure in gilts and sows, resulting in embryonic and fetal losses worldwide. Epitope mapping of PPV is important for developing new vaccines. In this study, we used spot synthesis analysis for epitope mapping of the capsid proteins of PPV (NADL-2 strain) and correlated the findings with predictive data from immunoinformatics. The virus was exposed to three conditions prior to inoculation in pigs: native (untreated), high hydrostatic pressure (350 MPa for 1 h) at room temperature and high hydrostatic pressure (350 MPa for 1 h) at − 18 °C, and was compared with a commercial vaccine produced using inactivated PPV. The screening of serum samples detected 44 positive spots corresponding to 20 antigenic sites. Each type of inoculated antigen elicited a distinct epitope set. In silico prediction located linear and discontinuous epitopes in B cells that coincided with several epitopes detected in spot synthesis of sera from pigs that received different preparations of inoculum. The conditions tested elicited antibodies against the VP1/VP2 antigen that differed in relation to the response time and the profile of structurally available regions that were recognized.

Foodborne viruses: Detection, risk assessment, and control options in food processing

In a recent report by risk assessment experts on the identification of food safety priorities using the Delphi technique, foodborne viruses were recognized among the top rated food safety priorities and have become a greater concern to the food industry over the past few years. Food safety experts agreed that control measures for viruses throughout the food chain are required. However, much still needs to be understood with regard to the effectiveness of these controls and how to properly validate their performance, whether it is personal hygiene of food handlers or the effects of processing of at risk foods or the interpretation and action required on positive virus test result. This manuscript provides a description of foodborne viruses and their characteristics, their responses to stress and technologies developed for viral detection and control. In addition, the gaps in knowledge and understanding, and future perspectives on the application of viral detection and control strategies for the food industry, along with suggestions on how the food industry could implement effective control strategies for viruses in foods. The current state of the science on epidemiology, public health burden, risk assessment and management options for viruses in food processing environments will be highlighted in this review.

Persistence of Hepatitis A Virus in Fresh Produce and Production Environments, and the Effect of Disinfection Procedures: A Review

Although information is limited, it is evident that prolonged persistence of infectious Hepatitis A virus (HAV) is a factor in the transmission of the virus via fresh produce. Consequently, data on persistence of the virus on produce, and in environments relevant to production, such as soils, water and surfaces, are required to fully understand the dynamics of transmission of HAV via foods. Furthermore, information on effective disinfection procedures is necessary to implement effective post-harvest control measures. This review summarises current information on HAV persistence in fresh produce and on relevant disinfection procedures. On vegetables, HAV can remain infectious for several days; on frozen berries, it can persist for several months. HAV can remain infectious on surfaces for months, depending on temperature and relative humidity, and can survive desiccation. It can survive for several hours on hands. Washing hands can remove the virus, but further data are required on the appropriate procedure. Chlorination is effective in water, but not when HAV is associated with foodstuffs. Bleach and other sodium hypochlorite disinfectants at high concentrations can reduce HAV on surfaces, but are not suitable for use on fresh produce. There is only limited information on the effects of heating regimes used in the food industry on HAV. HAV is resistant to mild pasteurisation. Some food components, e.g. fats and sugars, can increase the virus' resistance to higher temperatures. HAV is completely eliminated by boiling. Quantitative prevalence data are needed to allow the setting of appropriate disinfection log reduction targets for fresh produce.

Effect of Process Temperature on Virus Inactivation during High Hydrostatic Pressure Processing of Contaminated Fruit Puree and Juice

High pressure processing (HPP) can inactivate pathogens and retain fruit qualities. Elevated HPP pressure or time increases virus inactivation, but the effect of temperature is not consistently observed for norovirus and hepatitis A virus. In the present study, the effectiveness of HPP holding temperatures (<40°C) and pressures were evaluated for inactivating surrogates (murine norovirus [MNV] and MS2 coliphage) in pomegranate and strawberry juices and strawberry puree using a 24-liter HPP system. The holding temperature was established by setting the HPP initial temperature via pretrials. All trials were able to arrive at the designated holding pressure and holding temperature simultaneously. MNV inactivation in juices was conducted at 300 MPa for 3 min with various holding temperatures (10 to 30°C). A regression equation was derived, Y = -0.08 × X + 2.6 log PFU, R² = 0.96, where Y is the log reduction and X is the holding temperature. The equation was used to predict a 2.6-log reduction in juices at 0°C holding temperature and indicated that MNV inactivation was inversely proportional to temperature increase. MNV survival during HPP did not differ significantly in pomegranate and strawberry juices. However, MS2 coliphage inactivation was greater as the holding temperature increased (from 15 to 38°C) at 600 MPa for 3 min. The increased inactivation trend is presumably similar to that for hepatitis A virus, but the holding temperature was not correlated with the reduction of HPP-resistant MS2 in strawberry puree. When the HPP holding pressure was evaluated independently in strawberry puree, a 5-log reduction of MNV was predicted through regression analysis at the holding pressure of 424 MPa for 3 min at 20°C. These parameters should inactivate >5 log PFU of MNV in juices, based upon a greater inactivation in berry juice than in puree (1.16-versus 0.74-log reduction at 300 MPa). This research illustrates use of predictive inactivation and a feasible means for manipulating HPP parameters for effective virus inactivation in fruit juices and puree.